1. Field
Embodiments relate to the adjustment of the number of tasks for a cache storage scan and destage application based on the type of elements to be destaged from the cache storage.
2. Background
A storage controller may control access to storage for one or more host computational devices that may be coupled to the storage controller over a network. The storage controller may include a cache storage, and a storage management application that executes in the storage controller may manage a plurality of secondary storage devices, such as disk drives, tape drives, flash drives, direct access storage devices (DASD), etc., where the secondary storage devices are coupled to the storage controller.
A host computational device may send Input/Output (I/O) commands to the storage controller and the storage controller may execute the I/O commands by using the cache storage of the storage controller and the secondary storage devices that are coupled to the storage controller.
While the cache storage is relatively fast in terms of I/O access in comparison to the secondary storage devices, the cache storage is relatively smaller in storage capacity in comparison to the secondary storage devices. Additionally, the cache storage may include volatile memory that may be lost in certain situations (e.g., in the event of a power failure). Therefore, the cache storage is periodically (e.g., every one hour) scanned and data that is modified by I/O commands in the cache storage are destaged (i.e., moved) from the cache storage to the secondary storage, to make room in the cache storage for satisfying new I/O commands and for safely securing the data. If there is data loss in the cache storage or data is unavailable in the cache storage, then the data may be retrieved from the secondary storage.